Lesson 28-General Safety Practices

General Safety Rules:
1. Always keep the shop clean & orderly.
2. All materials & tools must be stored in appropriate areas of the shop.
3. Remove all obstructions when working.
4. Avoid running & making jokes while working.
5. Handle edge-cutting tools properly & carefully.
6. Always keep your hands free from oil & grease.
7. The work area must be well lighted.
8. Handle finishing materials carefully & close chemical containers immediately after using.
9. Always keep your eyes & mind focused on what you're doing.
10. Make a practice to always remind your classmates/co-workers not to violate safety rules in the shop.
11. It is also a safety practice to always help your classmates/colleagues if necessary.Be thoughtful.
12. Report all injuries immediately to your teacher.
13. Smoking in the shop is strictly prohibited.
14. Display safety precaution signs& charts in the shop.

Lesson 27-Orthographic Sketching

* Orthographic Drawing-is the process of representing the exact size & shape of an object in 2 or more views as they are seen perpendicularly from it's surfaces.
6 Principal Views of an Object:
1. Top View
2. Front View
3. Right Side View
4. Left Side View
5. Back/Rear Viiew
6. Bottom View
Guidelines in Orthographic Projection:
1. Locate the center of your drawing paper & draw vertical & horizontal axis.
2. Draw the Front View at the lower left quadrant.
3. Draw the Top View at the upper left quadrant above the Front View.
4. Draw the Right Side View at the lower right quadrant beside the Front View.
5. The Front View is the same as the Top View.
6. The height of the Front View is the same as the Right Side View.
7. The width of the Top View is the same as the Right Side View.
8. The nearest edges of the views to the 2 axes is about 3/4".
9. For accuracy,use projection lines.
10. Use 45 deg.triangle to project the Top View to Right Side View.
11. Dimension lines are placed between views.
12. Names of views are written outside the views.

Lesson 26-Pictorial Sketching

*Pictorial Sketchingis a type of drawing whose main objective is to present the object as it appears to the eye of the viewer(like a picture).

3 Kinds of Pictorial Drawing;

1. Isometric

2. Oblique

3. Perspective

Isometric Drawing-is a drawing wherein the object is represented by 3 sides seen at 1 time.It is derived from the Greek words"Iso" means equal & "Metric" means measure.

Steps in Sketching Isometric Box:

1. Draw 3 axes-vertical axis,left 30 deg.cross axis & right 30 deg.cross axis.

2.Layout the principal measurements.

3.Draw the box.

4. Draw the details.

5. Trace the visible edges.

Lesson 25-Freehand Drawing

*Freehand Drawing-referred to as Artist's Drawing because it is done without the use of straight edge instrument.Synonym is "Sketch".

Techniques in Sketching Lines:

1. Horizontal Lines-sketched from left to right.

2. Vertical Lines-sketched from top to bottom.

3. Inclined Lines-sketched from left to right diagonally.

4. Short lines-sketched with finger movement.

5. Long lines-sketched with arm movement.

6. Circles-may be sketched by radii method or 1 or 2 stroke.

7. Elipse-sketched with 1 or 2 strokes or parallelogram method.

8. Triangle-draw thin perpendicular lines mark off to the desired size along vertical & horizontal lines.Draw straight lines on the marks parallel to the vertical & horizontal lines.

9. Squares & Rectangles-are sketched by drawing cross axes at an angle of 90 degree mark equal distances from the vertical center for the length & equal distances fro the horizontal center for the width. Sketch the 4 sides to complete the object.

Lesson 24-Mensuration

2 Systems of Measurement:
1. English System
2. Metric System
The English System of Measurement
*Symbols used in the English System
Inch-in(")
Foot-ft.(')
Yard-yd.
Mile-mi.
*English System Equivalent
1 foot=12 inches
1 yard=3 feet
1 yard=36 inches
1 mile=4,860 feet
1 mile=1,620 yards
The Metric System of Measurement
*Symbols in the Metric System
millimeter-mm
centimeter-cm
decimeter-dm
meter-m
kilometer-km
decameter-Dm
hectometer-hm
* Metric System Equivalent
1 cm=10mm
1 dm=10 cm=100mm
1 m=10 dm=100cm=1,000mm
1 km=1,000m=10,000dm=100,000cm=1,000,000 mm

Lesson23-Alphabets of Lines

*Drafting-is a language of lines & symbols.
Classifications of Lines according to Use:
1. Borderlines-it surrounds a drawing.
2. Visible or Object Lines-it represents the visible edges of an object.
3. Hidden Lines-it represents the hidden features of an object.
4. Center Line-it represents the axis or center of objects with symmetrical shapes.
5. Dimension Lines-it is used to indicate the measurement of an object.
6. Extension Lines-it shows the extent or limit of the measurement.
7. Projection Lines-it projects 1 view to another.And sometimes called extension lines.
8. Leader Line-it indicates the measurement & name of a part.
9. Reference Line-it is used to label the parts of an object.
10. Limiting Line or Long Break Line-it is used to break objects that are very big to be drawn on paper.